1. Field of the Invention
The invention relates to a process to prepare film forming polymeric material compositions, which may be useful as a component in photoresist formulations.
2. Background of the Invention
Photoresist formulations are used to create and transfer an image pattern onto a selected substrate surface, such as silicon wafer used in making integrated circuits or computer chips. The photoresist formulations are spin-coated and baked on the silicon wafer; the coated wafers are exposed to a selected radiation through a photomask that contains an image pattern to be transferred on to a silicon wafer. The radiation exposed areas of the photoresist film undergo photochemical reactions changing the exposed portions of the photoresist film. In a positive tone resist, the exposed areas of the film become more soluble than unexposed film in an alkaline developer thereby creating a difference in solubility. This difference in alkaline solubility creates a pattern in the photoresist layer that is critical for further process steps such as etching of substrate and deposition of a conductive metal to create inter-connects on silicon wafer.
Due to shrinking patterns, photoresist formulations capable of forming more defined and smaller patterns are required. However, current photoresist formulations have been observed to lose definition at the increasing processing requirements of the new image transfer pattern processes.
It would be desirable to form photoresist formulations with improved properties for use in the higher processing requirement methods for image pattern transfer to substrates.